The purpose of this study is to extend into the middle and high school years (ages 11 through 15; grades 5 though 9) a prospective longitudinal research project describing the developmental and behavioral progress of very low birth weight children (VLBW less than 1500 grams). The specific aims of the project are to: (1) Compare the school achievement, school and social adjustment, cognitive processing abilities and behavioral styles of children who were VLBW with normal birth weight peers; (2) Provide clinicians and researchers with information about the specific cognitive and behavioral processes and characteristics of children who were very low birth weight; (3) Analyze the interplay of the multiple factors that influence outcome in VLBW; (4) Identify antecedent variables which predict school achievement and school and social adjustment in children who were VLBW. The 98 subjects are in three groups: 39 children who were VLBW; 32 normal birth weight schoolmates who have been matched for age, birth order, maternal education, socioeconomic status, gender and race; and 27 siblings of the VLBW children. Data Is gathered during observations, interviews and psychological testing in the home, from ophthalmologic examinations; and from teacher and school records. The instruments used in the study measure intellectual and school achievement, temperament, social competencies, behavior problems, health behaviors, and family, peer and school supports and prohibitions. Specific cognitive processing skills are measured by neuropsychological testing and ocular examinations. Data from the first ten years of the study on perinatal adversity, biological immaturity, the home environment, development, cognitive processing and behavioral characteristics are also used in data analysis. Data are analyzed using analysis of variance, repeated measures Anova, and regression analysis.